Remote Water Heaters?
 

I got a tankless water heater a year and a half ago and I've been impressed with the result. But one result that doesn't impress me is that now I worry about turning on my sink for just a bit of hot water. My tankless heater saves in the long run, but it required a bigger exhaust pipe because when it is running it is a monster. I hate to fire it up just to clean up my blender.

So...I've had in mind for a while to get a remote water heater on my sink and I thought that what I had in mind would be on the market, but I don't see one. I would like an electric one that I could just hook my hot water tap up to instead of the line to the water heater and quick heat water. All I can find at stores is 1/3, 2/3, and 3/4 gallon tanks and I don't want to go back to a tank. Does anyone know of one like I want?

You can get small tankless electric water heaters. They also suck tons of power while they are on though.

Here are a couple manufacturers:

Stiebel Eltron | Tankless Water Heaters, Solar Hot Water Systems, Hand Dryers, Electric Heaters
PowerStar Tankless | Electric Water Heaters | Bosch Hot Water | Energy Efficient | BoschHotWater.com

What about heating some water in the microwave... Only need two cups? Use a measuring cup to heat two cups! It's even easy to pour!

Another option is to use an electric kettle or coffee maker if you need only a little hot water.